Dyeing of textile materials using



United States Patent DYEING 0F TEXTILE MATERIALS USING MOLTEN METAL Robert S. E. Hannay, Edinburgh, Scotland, and William Kilby, Lancaster, England, assignors to Standfast Dyers and Printers Limited No Drawing. Application May 19, 1952, Serial No. 288,761

Claims priority, application Great Britain May 26, 1951 12 Claims. (Cl. 81)

The present application is a continuation-in-part of application Serial No. 722,042, filed January 14, 1947, and now forfeited in favor of application Serial No. 407,- 962, filed February 3, 1954, which has issued as Patent No. 2,693,995.

This invention relates to a process of dyeing textile materials in which the material after application of the dye thereto is passed through a bath of molten metal. British patent specification No. 620,584 describes such a process which may use an alloy such as Woods metal, and in which the dye liquor may fioat on the surface of the molten metal; alternatively the dye liquor may be padded on to the material before entering the molten metal.

It has been observed that contact of molten alloys such as Woods alloy with wet textile materials produces a slight reducing action which has an adverse effect on the colour of some dyestufis which have been used in aqueous solution for impregnation of the textile. Such dyestuffs are known to be affected by reducing agents and may even be completely destroyed by strong reducing agents. They are to be found principally amongst the classes known as wool dyes and acetate rayon dyes. Examples of such dyestuffs are:

Wool dyes:

Alizan'n Fast Green GGW Carbolan Brilliant Green SGS Lissamine Fast Violet 2138 Polar Brilliant Blue RAW Solway Blue 3GA Carbolan Blue BS Solway Purple (C. l. 1073) Acetate rayon dyes:

Duranol Scarlet B Duranol Scarlet 2G Duranol Red 2B Duranol Blue Green B Duranol Brilliant Blue G Duranol Blue 26 Such dyestuifs are referred to hereinafter as dyestuffs as aforesaid. It is the purpose of this invention to make possible the use of such dyestuffs by countering the reducing action of the metal.

In accordance with the present invention, we provide a process of dyeing textile materials with dyestuffs as aforesaid, in which the material after application of an aqueous dye liquor thereto is passed through a bath of molten metal, characterised by the fact that the material prior to entering the molten metal is treated with a mild oxidising agent which tends to counteract the reducing action of the molten metal. Preferably such oxidising agent is added to the aqueous dye liquor, but it may be applied in any convenient manner to the material, e. g., by padding or spraying.

The oxidising agent may be, for example, the sodium salt of rn-nitrobenzene sulphonic acid and the sodium salt of nitro-toluene-p-sulphonic acid.

ice

The mildness of the oxidising agent is limited on the one hand by the desirability that it should not be strong enough to destroy the dyestufi (by bleaching) or to oxidizev rapidly the molten metal or its alloy components. Ex-

amples of suitable stronger oxidising agents are:

Sodium ortho-vanadate Sodium chlorate (neutral dye bath) Sodium nitrite (neutral dye bath) At the other end of the scale any oxidising agent however mild would have some beneficial effect with some dyes.

The following examples show the composition of some dye liquors made up according to the improved process:

Example 1.Dyeing of wool fabricwith acid dyes Percent Bismuth 50 Lead 26.7

Tin 13.3

Cadmium 10 and has temperature 100 C. Dry scoured woolen fabric is preheated by passing over steam heated cylinders so that it enters the dye with a temperature of 90 C. The fabric speed is 20 yards per minute giving immersion times of 0.67 second for the dye liquor and 10 seconds for the molten metal. The fabric leaves the metal through a wash liquor floating on the exit surface and this aqueous bath (temperature 90 C.) contains 1% of commercial acetic acid. The fabric is finally rinsed and dried and is coloured purple.

Example 2.Dyein'g acetate rayon fabric or nylon fabric with dispersed acetate dyes 1O grms./litre of Duranol Red 2B 300 Pdr. a dispersed acetate dye supplied by I. C. I. Ltd.

5 grms./litre soap.

l0 grms./litre sodium-m-nitrobenzene-sulphonate.

The dye liquor described is made up, stored and pumped to the surface of the molten metal at 80 C. the metal temperature being 95 C. Dry scoured acetate rayon fabric and nylon fabric is preheated by passing through a hot air chamber so that it enters the dye with a temperature of 80 C. The fabric speed is 30 yards per minute giving immersion times of 0.44 second for the dye and 6.7 seconds for the metal. The fabric leaves the metal through hot water (temperature C.) floating on the exit surface of the metal and is finally rinsed and dried. It is coloured red.

Example 3.-Dyeing of wool fabric with acid dyes 5 grms./litre Lissamine Fast Violet 2B8 (imperial Chemical Industries) 10 grms. per litre Teepol X (wetting agent) 10 grms. per litre ethyl lactate 5 grms. per litre sodium nitrite.

This dye liquor is pumped to the surface of the molten metal bath at 98 C.

The metal alloy has the composition:

52.5% Bismuth 15.5% tin 32.0% lead and is maintained at 98 C.

Dry, scoured woolen fabric is preheated by passing over steam-heated cylinders so that it enters the dye with a temperature of 98 C. The time of immersion in the molten metal is 15 seconds and the fabric leaves the metal by way of an exit floating liquor containing 1% of 80% acetic acid and at a temperature of 98 C. The fabric is further treated in continuous manner in 5 grms. per litre acetic acid (80%) for two minutes, then rinsed and dried to give a bright violet coloured fabric.

The following is an example showing the application of the oxidising agent to the material otherwise than by addition to the dye liquor:

Example 4.-Dyeing of wool fabric with acid dyes Scoured wool serge fabric is impregnated in a twobowl padding mangle with a liquor containing 10 grms. per litre sodium meta nitro-benzene sulphonate and I grams. per litre ethyl lactate. This fabric either in the wet condition or alternatively dried, is dyed by the method described in Example 1 but using the following dye liquor:

l0 grms. per litre Teepol X (wetting agent) (Shell chemicals) 5 grins. per litre of the acid dye Lissamine Fast Violet 2BS (I. C. I. Ltd.) (no colour index No.)

grins. per litre formic acid.

The fabric leaving the molten metal bath is rinsed and dried giving a coloured fabric which is brighter and bluer than a dyeing carried out in the absence of the pretreatment with oxidising agent.

Dye liquor used in a padder would have the same compositions as in the foregoing examples.

The invention is also applicable in conjunction with the inventions set forth in applicants copending applications, Serial Nos. 46,804; 90,995; 90,996 and 90,998, the first three applications being now abandoned and the last having issued as Patent No. 2,693,689.

We claim:

1. In a process of dyeing textile materials with dyestuifs which are adversely afiected by reducing agents in which the material after application of an aqueous 4 dye liquor thereto is passed through a bath of molten metal, the improvement which comprises incorporating into the impregnated material entering the molten metal a mild oxidizing agent incapable of exerting a rapid oxidizing influence upon the metal of the molten bath and also of insufficient strength to bleach the dyestufi said oxidizing agent having no greater oxidizing strength than sodium chlorate in a neutral bath.

2. A process according to claim 1, wherein the oxidising agent is added to the aqueous dye liquor.

3. A process according to claim 1, wherein the oxidising agent is contained in a liquor and the material is impregnated with the oxidising liquor prior to entering the dye liquor.

4. A process according to claim 3, wherein the material is impregnated with the oxidising liquor in a padding mangle.

5. A process according to claim 1 wherein the dyestutf V is an acid wool dye.

6. A process according to claim 1 wherein the dyestuff is an acetate rayon dye.

7. A process according to claim 1 wherein the aqueous dye liquor floats on the bath of molten metal and the textile material passes through said dye liquor and directly therefrom into and through said molten metal bath.

8. The process of claim 1, wherein the oxidizing agent is sodium-m-nitrobenzene-sulphonate.

9. The process of claim 1, wherein the oxidizing agent is sodium nitrotoluene-p-sulphonate.

10. The process of claim 1, wherein the oxidizing agent is sodium ortho vanadate.

11. The process of claim 1, wherein the oxidizing agent is sodium chlorate.

12. The process of claim 1, wherein the oxidizing agent is sodium nitrite.

Great Britain Jan. 23, 1952. France Oct. 10, 1944 

1. IN A PRCESS OF DYEING TEXTILE MATERIALS WITH DYESTUFFS WHICH ARE ADVERSELY AFFECTED BY REDUCING AGENTS IN WHICH THE MATERIAL AFTER APPLICATION OF AN AQUEOUS DYE LIQUOR THERETO IS PASSED THROUGH A BATH OF MOLTEN METAL, THE IMPROVEMENT WHICH COMPRISES INCORPORATING INTO THE IMPREGNATED MATERIAL ENTERING THE MOLTEN METAL A MILD OXIDIZING AGENT INCAPABLE OF EXERTING A RAPID OZIDIZING INFLUENCE UPON THE METAL OF THE MOLTEN BATH AND ALSO OF INSUFFICIENT STRENGTH TO BLEACH THE DYESTUFF SAID OXIDIZING AGENT HAVING NO GREATER OXIDIZING STRENGTH THAN SODIUM CHLORATE IN A NEUTRAL BATH. 